In vitro interactions of a new derivative of spicamycin, KRN5500, and other anticancer drugs using a three-dimensional model

PURPOSE

KRN5500 is a new derivative of spicamycin produced by Streptomyces alanosinicus and is known to have a wide range of antitumor activities against human cancer cell lines. Because of its unique structure, this compound seems to have a different mode of action from other antitumor drugs and nonoverlapping toxicities. Therefore, KRN5500 is expected to be a suitable candidate for combination chemotherapy.

METHODS

We investigated the effects of combinations of KRN5500 and other anticancer drugs on the growth of a human non-small-cell lung cancer cell line, PC14, using a revised three-dimensional model.

RESULTS

Synergism was observed when KRN5500 and cisplatin were combined at concentrations in the ranges 0.005 to 0.25 microg/ml and 0.025 to 0.25 microg/ml, respectively. In combination with carboplatin, an analog of cisplatin, and etoposide, a marked synergistic interaction was also found.

CONCLUSION

These results suggest the usefulness of combinations of KRN5500 with cisplatin, carboplatin or etoposide for chemotherapy for non-small-cell lung cancer.

Intraosseous epithelioid malignant peripheral nerve sheath tumor of the phalanx. Case report

We report the first case of intraosseous epithelioid malignant peripheral nerve sheath tumor (MPNST) occurring in the phalanx. The patient was a 50-year-old Japanese man with an intramedullary lytic lesion of the proximal phalanx. Microscopically, the tumor was composed of epithelioid cells or polygonal cells, forming large cell nests with central necrosis. Most tumor cells were diffusely and strongly immunopositive for S-100 protein and vimentin, and negative for cytokeratin, epithelial membrane antigen, carcinoembryonic antigen, alpha-smooth muscle actin, and HMB-45. Laminin-positive material was discontinuously demonstrated between the individual tumor cells. Electron microscopy showed prominent external lamina. Our case indicated that laminin is useful for differentiating epithelioid MPNST from metastatic carcinoma and malignant melanoma.

Combination effects of TAS-103, a novel dual topoisomerase I and II inhibitor, with other anticancer agents on human small cell lung cancer cells

PURPOSE

TAS-103 [6-((2-(dimethylamino) ethyl)amino)-3-hydroxy-7H-iindeno(2,1-c)quinolin-7-one dihydrochloride] is a newly synthesized dual inhibitor of topoisomerase I and II. Since anticancer drugs are used in combination with other drugs for effective chemotherapy, we investigated the cytotoxic effect of TAS-103 in combination with other conventional anticancer agents, such as cisplatin, vindesine, doxorubicin, 5-fluorouracil, and the antitopoisomerase inhibitors SN-38 and etoposide in vitro.

METHODS

Inhibition of the growth of the human small-cell lung cancer cell line SBC-3 was evaluated using the tetrazolium dye (MTT) assay. Drug interactions were evaluated by isobologram analysis and the determination of combination indices supplemented by a three-dimensional model.

RESULTS

Simultaneous use of TAS-103 and cisplatin had a supraadditive effect, but combinations of TAS-103 with other drugs had an additive or marginally subadditive effect. Three-dimensional model analysis added more information about the synergistic concentration ranges of two drugs (cisplatin 200-400 nM and TAS-103 7 10 nM). Sequential use of TAS-103 and cisplatin had only an additive effect.

CONCLUSION

These results suggest that the concomitant use of TAS-103 and cisplatin has a greater cytotoxic effect on cancer cells than single drug use, and may provide a beneficial effect in the treatment of small-cell lung cancer.

Mitogen-activated protein kinase antisense oligonucleotide inhibits the growth of human lung cancer cells

Mitogen-activated protein kinase (MAPK) pathway is proposed to be a therapeutic target for cancer cells. In order to find the potential therapeutic usefulness of MAPK for cancer cells, the effect of EAS1, an antisense oligonucleotide for an MAPK, on cancer-cell-growth were investigated in vitro. EAS1 effectively inhibited the growth of several human lung cancer cell lines such as PC-14 cells upon exposure to 10-0-10-1 microM of EAS1 determined dye-formation (MTT) assay. The ED50 values were comparable to those obtained for the inhibition of MAPK activity, DNA synthesis. EAS1 arrested the PC-14 cells at the G2/M phase of cell cycle followed by apoptosis in a dose-dependent manner. In order to determine the factors which influence the cellular sensitivity against MAPK inhibition, the effect of EAS1 on H-ras-transformed murine fibroblast cells were compared with that on parental cells. The NIH3T3 cells transformed by the H-ras gene (PT22-3) showed higher sensitivity against the effects of EAS1. Because MAPK activity was activated by H-ras gene transfection in PT22-3, the status of the MAPK cascade in cells was the determining factor for the efficacy of EAS1. In addition, cell permeabilization by digitonin enhanced the growth inhibitory effect of EAS1. Penetration of the cell membrane by EAS1 is also crucial for the growth inhibitory effect of EAS1. In conclusion, MAPK is an important target for cancer treatment and MAPK antisense oligonucleotide is a potentially significant antitumor oligonucleotide.

Hypoalbuminemia accelerates erythrocyte membrane lipid peroxidation in chronic hemodialysis patients

BACKGROUND

Persistent hypoalbuminemia is a long-term poor prognostic factor in chronic hemodialysis patients.

PATIENTS AND METHODS

We investigated the correlation between the degree of peroxidation of erythrocyte membrane lipids, erythrocyte alpha tocopherol content, erythrocyte glutathione peroxidase activity and serum albumin concentration in twelve patients with uremia not undergoing hemodialysis and fifteen patients on maintenance hemodialysis.

RESULTS

The glutathione peroxidase activity in erythrocytes was higher in patients of uremia not undergoing hemodialysis than in chronic hemodialysis patients. A significant negative correlation was observed between the erythrocyte alpha tocopherol content and the degree of erythrocyte membrane lipid peroxidation in chronic hemodialysis patients. There was a statistically significant difference in the degree of erythrocyte membrane lipid peroxidation between patients with chronic hemodialysis-associated hypoalbuminemia and chronic hemodialysis patients having normal serum albumin levels.

CONCLUSION

This study suggested that serum albumin inhibits peroxidation of erythrocyte membrane lipids and that hemodialysis induces recovery of serum reductivity. We conclude that persistent hypoalbuminemia worsens the serum antioxidant activity in chronic hemodialysis patients and may contribute to increased oxidative cell damage.

Enhancement of cisplatin sensitivity in high mobility group 2 cDNA-transfected human lung cancer cells

To elucidate the role of high mobility group 2 protein (HMG2) in cis-diamminedichloroplatinum (II) (cisplatin, CDDP) sensitivity, we constructed a human HMG2-transfected human non-small cell lung cancer cell line, PC-14/HMG2. The HMG2 mRNA expression level was approximately twice those of parental PC-14 and mock-transfected PC-14/CMV. Gel mobility shift assay revealed a CDDP-treated DNA-protein complex in the nuclear extract of PC-14/HMG2, which was not found in the extracts of PC-14 and PC-14/CMV. This complex formation was subject to competition by CDDP-treated non-specific salmon sperm DNA, indicating that ectopic HMG2 recognizes CDDP-damaged DNA. PC-14/HMG2 showed more than 3-fold higher sensitivity to CDDP than PC-14 and PC-14/CMV. The intracellular platinum content of PC-14/HMG2 after exposure to 300 microM CDDP was 1.1 and 1.5 times that of PC-14 and PC-14/CMV, respectively. Cellular glutathione levels were not different in these cell lines. Repair of DNA interstrand cross-links determined by alkaline elution assay was decreased in PC-14/HMG2. These results suggest that HMG2 may enhance the CDDP sensitivity of cells by inhibiting repair of the DNA lesion induced by CDDP.

Mucosa-associated lymphoid tissue (MALT) lymphoma of the thyroid: report of a case

The patient was 59-year-old Japanese woman who presented with a neck swelling. Ultrasonography and computed tomography demonstrated a round tumor in the thyroid right lobe measuring 2.5 x 1.5 cm in size. A right hemithyroidectomy with lymph node dissection was performed. Histopathological findings demonstrated low-grade B cell lymphoma of the mucosa-associated lymphoid tissue (MALT) associated papillary microcarcinoma. A previous report showed an excellent prognosis of MALT lymphoma of the thyroid without capsular invasion or lymph node involvement. We also describe the concept of MALT lymphoma as a primary lesion in which lymphoid tissue is not present in the normal state.

The C-terminal domain of p53 catalyzes DNA-renaturation and strand exchange toward annealing between intact ssDNAs and toward eliminating damaged ssDNA from duplex formation through preferential recognition of damaged DNA by a duocarmycin

The C-terminal domain of p53 may bind single-stranded (ss) DNA ends and catalyze renaturation of ss complementary DNA molecules, suggesting a possible direct role for p53 in DNA repair (Proc. Natl. Acad. Sci. USA, 92, 9455-9459, 1995). We found that DU-86, a duocarmycin derivative which alkylates DNA, bound ssDNA and enhanced the DNA binding activity of the p53 C-terminus. DU-86 weakened p53-mediated catalysis of complementary ssDNA renaturation. p53 C-terminus catalyzed DNA strand transfer toward annealing between intact ssDNAs and toward eliminating DU-86-damaged ssDNA from duplex formation. These results suggest that p53, via the C-terminal domain, may play a direct role in DNA repair by preferential recognization and elimination of damaged DNA.

Biochemical renal manifestations induced by consecutive administration of gentamicin in rats

In the present study, we investigated the generation of lipid peroxides and changes in total phospholipid levels in the kidney tissue of rats with acquired resistance to gentamicin (GM). GM resistance was induced in Sprague-Dawley male rats by subcutaneously administering each rat a dose of 80 mg/kg/day of GM for 40 consecutive days. Twelve days after the GM administration, serum urea nitrogen peaked at 35 mg/dl. The urinary creatinine excretion progressively decreased, beginning 4 days after the start of GM administration. The fractional excretion of sodium progressively increased, beginning 4 days after the start of GM administration, peaking on the 10th day. However, despite the continuation of GM administration, the urinary creatinine excretion gradually increased, and the serum urea nitrogen concentrations recovered to previous levels after 21 days. We also analyzed the relationship between the acquired resistance to GM and changes in the reduced glutathione content and glutathione peroxidase activity. Simultaneously, we investigated sequential changes in the activities of phospholipase A2 and phospholipase C, which release peroxidized membrane phospholipids into the cytoplasm via hydrolysis, as well as the relationship between changes in the kidney tissue phospholipid composition (sphingomyelin/phosphatidylcholine ratio) and renal function. We found that (1) the kidney tissue glutathione content rapidly decreased after GM administration before subsequently increasing and being maintained at a higher level; (2) the glutathione peroxidase activity showed a persistent decrease after GM administration; (3) the kidney tissue phospholipase A2 activity decreased after GM administration, while the phospholipase C activity exhibited a sustained increase from 21 days, and (4) the spingomyelin/phosphatidylcholine ratio decreased on the 4th day before stabilizing when acquired resistance was obtained. Based on these findings, we conclude that an increased supply of reduced glutathione and the induction of an antioxidase, substituting for glutathione peroxidase, may play a significant role in the acquisition of resistance to acute renal failure which occurs with continuous GM administration. Improved membrane fluidity, achieved by maintenance of the membrane phospholipid composition by increased phospholipase C activity, may be an additional factor contributing to the recovery of the renal function.

Oxyphilic cell variant of endometrioid adenocarcinoma

A case of oxyphilic cell variant of endometrioid adenocarcinoma is presented. To the best of our knowledge, there have been only three such cases reported in the English literature. The patient was a 35-year-old Japanese female (gravida 0, para 0). She was slightly obese with profuse vaginal bleeding. Histological examination of the resected uterus revealed endometrioid adenocarcinoma with an exclusive oxyphilic cell component. There was no evidence of myometrial invasion nor lymph node metastases. Reported cases of oxyphilic cell variant of endometrioid adenocarcinoma, including the present case, were stages 0-1 and grades 1-2. Although further study is necessary to evaluate this variant, oxyphilic cell variant seems to be an early stage of adenocarcinoma and should be differentiated from eosinophilic metaplasia and other types of adenocarcinoma of the endometrium.

[Small cell lung cancer associated with nephrotic syndrome: remission after chemotherapy]

A 66 year-old man was found to have pointed out a 1-cm tumor shadow, on a chest X-ray film when he underwent a gastrectomy because of advanced gastric cancer. Five months after the operation, edema and proteinuria developed, and a chest X-ray film revealed enlargement of the tumor. There was no sign of recurrence of the gastric cancer. Nephrotic syndrome due to IgA-nephropathy and small cell lung cancer was diagnosed. Chemotherapy (carboplatin and etoposide) was effective against both the lung tumor and the nephrotic syndrome. Small cell lung cancer may have been involved in the pathogenesis of the nephrotic syndrome in this patient.

Increased expression of sialyl Lewis(x) antigen is associated with distant metastasis in lung cancer patients: immunohistochemical study on bronchofiberscopic biopsy specimens

The tumor-associated carbohydrate antigens sLe(x) and sLe(a) are known to be ligands of endothelial cell leukocyte adhesion molecule-1 (ELAM-1) and to be involved in hematogenous metastasis of human cancer cells. To determine whether expression of these carbohydrate antigens in lung cancer is associated with metastatic status, we immunohistochemically evaluated the expression of sLe(x) and sLe(a) in 52 bronchofiberscopic biopsy specimens obtained from patients with various stages of previously untreated lung cancer. The incidence of sLe(x) and sLe(a) positivity by immunostaining was 65.4 and 13.4%, respectively (P < 0.01). The incidence of sLe(x) positivity in patients with adenocarcinoma (94.7%) was significantly higher than in patients with squamous cell carcinoma (52.0%) and small cell carcinoma (28.6%) (P < 0.05). The high sLe(x) immunoreactivity correlated with metastasis to a distant organ (P < 0.05), but not with lymph node metastasis. The serum levels of these carbohydrate antigens measured by a serological assay correlated with their immunohistochemically detected expression (P < 0.01). These findings indicate that sLe(x) is expressed more frequently than sLe(a) in bronchofiberscopic biopsy specimens and plays an important role in distant metastasis in lung cancer patients.

Distinct interleukin-1beta-converting enzyme family proteases mediate cisplatin- and staurosporine-induced apoptosis of mouse proximal tubule cells

Interleukin-1beta converting enzyme (ICE) family proteases (caspases) are known to be implicated as important effectors of apoptotic pathways. The purpose of this study was to elucidate the role of ICE family proteases in apoptosis of mouse cells derived from the terminal proximal tubule (S3) treated with cisplatin, an anti-tumor drug, or staurosporine, a protein kinase C inhibitor. For this purpose, we measured the activities of ICE family proteases and examined the effects of tetrapeptide and viral ICE family protease inhibitors on the activities of ICE family proteases in and the degree of apoptosis of S3 cells treated with cisplatin and staurosporine. RT-PCR analysis revealed that S3 cells as well as mouse kidney express mRNA for ICE and CPP32, an ICE family protease. Results of enzymatic analysis, determination the degree of DNA fragmentation and cytotoxicity test suggest that CPP32 mediates cisplatin-induced apoptosis of S3 cells, whereas ICE family proteases other than CPP32 mediate staurosporine-induced apoptosis of S3 cells. In conclusion, distinct ICE family proteases mediate apoptosis of mouse proximal tubule cells depending on the stimuli to which the cells are exposed.

Occurrence and spontaneous remission of Graves' hyperthyroidism preceded by painless thyroiditis

A 45-year-old woman was referred to our hospital because of discomfort in the cervical region. Laboratory findings revealed thyrotoxicosis with positive TSH receptor antibodies, but acute inflammatory data were absent. After three weeks the thyroid hormone levels spontaneously decreased to hypothyroid levels, and thyroidal radioactive iodine uptake (RAIU) was below normal. A needle-biopsy specimen of the thyroid gland obtained two months later showed diffuse lymphocytic thyroiditis, and she was therefore diagnosed as having had painless thyroiditis. Two months after returning to euthyroidism, a second thyrotoxicosis developed. TSH receptor antibodies remained positive, but RAIU was slightly above normal, indicating Graves' hyperthyroidism. Treatment with antithyroidal drugs was commenced but was soon discontinued due to an allergic reaction. Although only beta-adrenergic antagonist was administered for treating the thyrotoxicosis, thyroid function was gradually normalized in parallel with the reduction in TSH receptor antibody. In this case, painless thyroiditis would be followed by Graves' disease and subsequent spontaneous remission.

In vitro enhancement of antitumor activity of a water-soluble duocarmycin derivative, KW-2189, by caffeine-mediated DNA-repair inhibition in human lung cancer cells

Duocarmycins, including KW-2189, bind in the minor groove of double-stranded DNA at A-T-rich sequences, followed by covalent bonding with N-3 of adenine in preferred sequences. We examined the effect of DNA-repair modulators, such as caffeine and aphidicolin, on the cytotoxicity of duocarmycins towards human lung cancer cells, as determined by dye formation assay. Caffeine (0.5 or 1 mM), but not aphidicolin, enhanced the growth-inhibitory activity of KW-2189, DU-86, and duocarmycin SA. Caffeine inhibited repair of DNA strand breaks induced by KW-2189, as assayed by the alkaline elution technique. This suggests that duocarmycin-induced DNA strand breaks, which are potentially lethal to cells, are repaired through a caffeine-sensitive pathway.

Anti-apoptotic genes, bag-1 and bcl-2, enabled hybridoma cells to survive under treatment for arresting cell cycle

Hybridoma 2E3-O cells were transfected with bcl-2 alone or with bcl-2 and bag-1 in combination. The bcl-2/bag-1 transfectant survived maintaining viability above 75% for almost 5 days when the cells were treated with excess (30 mM) thymidine for arresting cell cycle, whereas the mock transfectant survived for only 2 days, and the bcl-2 alone transfectant lived for 4 days. Owing to this extended viable culture period, the bcl-2/bag-1 transfectant produced twofold amount of antibody in comparison with the mock transfectant in non-proliferating state prepared by the excess thymidine treatment. When their proliferation was arrested by serum limitation, the bcl-2/bag-1 transfectant and the bcl-2 alone transfectant survived for 3 days maintaining viability above 75% while the mock transfectant survived only 1 day. The bcl-2/bag-1 transfectans produced the antibody at the rate three times as high as the bcl-2 alone transfectant and the mock transfectant in non-proliferating state established by serum limitation. Such genetic engineering of hybridoma cells for improving survival in the non-proliferating state will be useful for using nutrients in culture medium efficiently to produce antibody, since nutrients could be diverted from cell proliferation to antibody production in such non-proliferating viable cell culture.

p16INK4 expression is associated with the increased sensitivity of human non-small cell lung cancer cells to DNA topoisomerase I inhibitors

Inactivation of p16INK4, an inhibitor of cyclin-dependent kinases 4 (CDK4) and 6 (CDK6), may be essential for oncogenesis in non-small cell lung cancer (NSCLC). We examined the sensitivity of two clones of p16INK4-transfected NSCLC cell line with homozygous deletion of p16INK4, A549/p16-1 and 2, to DNA topoisomerase I (topo I) inhibitors. A549/p16-1 and -2 showed 7.7- and 9.1-fold increases in sensitivity to CPT-11 (11,7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin ), respectively, compared with A549 cells. Ectopic p16INK4-expressing cells also showed approximately 4.0-fold increase in sensitivity to SN-38 (7-ethyl-10-hydroxycamptothecin), the active metabolite of CPT-11, compared to the parent cells. The topo I-mediated DNA relaxation activities of ectopic p16INK4-expressing cells were approximately 5 times higher than those of the parent cells. Northern and western blot analyses indicate that these increased topo I activities of ectopic p16INK4-expressing cells were due to an elevated topo I mRNA level and an increase in topo I protein. The chemosensitivity to topo I inhibitors, topo I mRNA level, protein content and activity of a p16INK4 revertant, lacking functional p16INK4, tended to be restored toward those of the parental phenotype to some extent. These results suggest that p16INK4 expression is closely associated with the increased sensitivity of ectopic p16INK4-expressing NSCLC cells to topo I inhibitors. The up-regulation of topo I mRNA level, protein content and activity may be responsible for this hypersensitivity.

[Trend of bacterial meningitis in children over a 14 year period (1981 through 1994) in Japan--an analysis based on studies in 27 institutions]

We observed 266 children with purulent meningitis in 27 institutions in Japan during the 14 years from 1981 on dividing these years into 3 periods, 1981-1985, 1986-1990 and 1991-1994, and studied the trend of causative organisms identified in 254 among the 266 patients. Their ages were less than 3 months after birth in 50 children and 3 months or older in 216: there were 141 boys and 125 girls. The causative organisms were H. influenzae in 134 patients and S. pneumoniae in 50, most of them being aged 3 months or older. Next to the above bacteria ranked S. agalactiae in 29 and E. coli in 12, many of the patients were aged less than 3 months. Staphylococcus spp. was found in 7 patients and about 70% of them were aged 3 months or older. L. monocytogenes was found in 4 patients and N. meningitidis in 3 and they were aged 3 months or older in both patient groups. S. pyogenes, Enterococcus spp., Peptostreptococcus spp., P. Mirabilis and Enterobacter spp. were detected each in 1 patient. The causative organism was unknown in 21 patients and there was no double infection. H. influenzae were detected in 18 patients in 1981-1985 period (36.7%), in 56 in 1986-1990 (54.9%) and in 60 in 1991-1994 (63.8%) showing an increasing tendency, but S. pneumoniae exhibited neither an increasing nor decreasing tendency. There was a decreasing tendency with S. agalactiae and E. coli, but the details were not clear because there were few patients aged less than 3 months. Although the period of coexistence of 4 main bacterial species was not made clear in this study. Listeria is considered to develop mainly in the early childhood, and we believe that the conventional way of using a cephem preparation and ampicillin combined for patients under 6 years need not be altered. However, panipenem (phonetic) is likely to be effective for insensible S. pneumoniae for the time being.

Circumvention of glutathione-mediated mitomycin C resistance by a novel mitomycin C analogue, KW-2149

A novel antitumor antibiotic 7-N-[2-[[2-(gamma-L-glutamylamino)ethyl]dithio]ethyl] mitomycin C (KW-2149), an analogue of mitomycin C (MMC), is activated by thiol molecules, such as glutathione (GSH). To clarify the relationship between cellular GSH levels and the cytotoxicity of KW-2149, a murine fibroblast cell line (NIH/3T3) was transfected with human gamma-glutamylcysteine synthetase (gamma-GCS) cDNA, which codes a rate-limiting enzyme of GSH synthesis. Transfected cells (3T3/GCS) displayed increased gamma-GCS mRNA levels, gamma-GCS activity and GSH content, compared with NIH/3T3 cells. 3T3/GCS cells exhibited a 4.4-fold resistance to MMC, but not to KW-2149 (x 0.69), using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, suggesting that the increased cellular GSH levels did not affect the growth-inhibitory effect of KW-2149. KW-2149 exerted a greater growth-inhibitory effect than MMC on cisplatin- and doxorubicin-resistant cells with cross-resistance to MMC. KW-2149 exhibited a greater growth inhibitory effect than MMC not only on cells with GSH-mediated MMC resistance but also on cells with acquired resistance. We thus conclude that KW-2149 might be a clinically useful drug.

[Antimitotic agents]

Microtubules are one of the major filament of the cytoskelton and play a role in various biological functions such as mitosis, cell motility and intracellular transport. Therefore, microtubules are considered one of the most important molecular targets for cancer chemotherapy. Tubulin is one of the major microtubular components, and its polymerization and depolymerization regulate microtubular dynamics. Other microtubular components such as microtubule-associated protein (MAPs), actin, and intermediate and microfilaments have also been demonstrated to be involved in microtubular dynamics. Recent studies provide evidence that the functions of MAPs and filaments in microtubule assembly are regulated by phosphorylation, which is catalyzed by mitogenactivated protein kinase (MAP kinase) and cdc2 kinase. Antimitotic agents that disrupt microtubules can be classified in two categories according to the mechanism of action, vinca alkaloids and taxanes. Vinca alkoloids, estramustine, rhizoxin, and E7010 inhibit microtubule polymerization. In contrast, taxanes such as paclitaxel and docetaxel promote polymerization of microtubules and enhance microtubule stability. We have demonstrated that paclitaxel inhibits the catalytic activity of MAP kinase and cdc2 kinase in lung cancer cell lines. This biological effect may be responsible for the increased affinity between MAP2 and tubulins, resulting in promotion of microtubule assembly. Factors that contribute to the resistance to antimitotic agents include intracellular accumulation of the drugs, genetic or functional alternations in tubulin, and alternations in MAP kinase cascade. Antimitotic agents showed a broad spectrum of preclinical antitumor activity. Clinical trials of taxanes revealed that they were effective for several cancers which were advanced or resistant against other anticancer drugs, especially for breast cancers, ovarian cancers and non-small cell lung cancers.

Proximal 5'-flanking sequence of the human gamma-glutamylcysteine synthetase heavy subunit gene is involved in cisplatin-induced transcriptional up-regulation in a lung cancer cell line SBC-3

The contribution of the 5'-flanking sequence of the human gamma-glutamylcysteine synthetase heavy subunit (gamma-GCSh) gene to cisplatin-induced transcriptional up-regulation was studied using various human growth hormone reporter constructs which were transfected to a human lung cancer cell line SBC-3. Cisplatin at the concentration of 3 microM increased the transcriptional activity of the longest sequence from -1,413 to +91 bp of the gamma-GCSh gene to 246% of that in non-exposed cells. The distal sequence from -1,413 to -193 bp was shown to negatively regulate transcriptional activity in both cisplatin-exposed and non-exposed cells using deletion and thymidine kinase (TK) promoter-linked constructs. Cisplatin increased the transcriptional activity of the proximal GC-rich sequence from -192 to +91 bp to 340%, of which magnitude was the maximum among deletion constructs. A deletion from -108 to -28 bp, or +34 to +91 bp significantly decreased cisplatin-induced increases in transcriptional activity from 258 to 105%, or 340 to 160%, respectively. When the sequence from -108 to -22 bp, or +26 to +91 bp was linked to the heterologous TK promoter, cisplatin increased the transcriptional activity to 171 or 181%, respectively, from that of 128 or 137%, respectively, in non-exposed cells. These findings indicate that the proximal sequence from -192 to +91 bp of the gamma-GCSh gene, especially from -108 to -28 bp, and +34 to +91 bp, is involved in cisplatin-induced transcriptional up-regulation in SBC-3 cells.

[Cytokine producing ability of peripheral blood mononuclear cells in the clinical course of pulmonary tuberculosis]

Interferon-gamma (IFN-gamma) and interleukin-10 (IL-10)-producing ability of peripheral blood plastic-dish adherent cells and non-adherent cells obtained from patients with active pulmonary tuberculosis (N = 17) and healthy controls (N = 14) upon stimulation with purified protein derivatives (PPD) were assessed. Adherent cells and non-adherent cells were obtained two times from each patient with active pulmonary tuberculosis without any underlying diseases, on admission before the initiation of administering anti-tuberculous drugs and 2 months later from the negative conversion of Mycobacterium tuberculosis in sputum culture. ELISA was performed to measure IFN-gamma and IL-10 levels in culture media of adherent cells and non-adherent cells stimulated with PPD. IFN-gamma levels produced by non-adherent cells on admission were significantly higher than that of healthy controls (p < 0.001). Elevated IFN-gamma levels on admission was reduced after treatment for tuberculosis (p < 0.03), but still remained higher than that in healthy controls. IL-10 levels of non-adherent cells of patients were lower than those of healthy controls, although the difference was not significant. IL-10 levels produced by non-adherent cells on admission correlated with the time needed for negative conversion of bacilli in sputum culture (p < 0.05). IL-10 level produced by adherent cells from nutritionally normal patients were significantly higher than that of healthy controls (p < 0.05), and elevated IL-10 level was significantly reduced after therapy (p < 0.05). In the normonourished patients, the time needed for negative conversion of the bacilli in sputum culture of patients kept higher level of IL-10 of non-adherent cells (N = 5) was significantly longer than that of patients reduced IL-10 level after therapy. These results suggest that IL-10 produced by monocytes may diminish the TH1 responses of patients with pulmonary tuberculosis.

Evaluation of synergism by a novel three-dimensional model for the combined action of cisplatin and etoposide on the growth of a human small-cell lung-cancer cell line, SBC-3

Although the combination of cisplatin and etoposide has been used as standard therapy for small-cell lung cancer, it is difficult to demonstrate combination effects between cisplatin and etoposide in vitro. We therefore adopted a 3-dimensional (3-D) model to analyze the combination effects of anticancer drugs, and compared the results of analysis by the new 3-D model with those obtained from traditional 2-D models for the cisplatin-etoposide combination. In this study, using a human small-cell lung-cancer cell line (SBC-3), 3-D model analysis clearly identified a relationship depending on the concentrations of both drugs, and demonstrated that peak synergy occurred at the higher concentrations of cisplatin and etoposide. Antagonistic interactions were noted with a nadir at low concentrations of etoposide and cisplatin. In contrast, 2-D models such as combination index and isobologam analysis fail to characterize the complex interactions between cisplatin and etoposide, since their joint effects are concentration-dependent. Combination index (CI) plots show that synergy is evident only for molar ratios of cisplatin: etoposide of 2:1 to 1:5. On isobologram analysis, synergy could be detected when great inhibitory effects on cell growth were present (high endpoint), but not with small inhibitory effects (lower endpoints). Thus, either synergy or antagonism may occur, but depend on the selection of variables, such as the molar ratios or the endpoints chosen for the experiments. This could explain the inconsistency in the in vitro combination effects reported to date. The 3-D model, which compensates for the above deficiencies of 2-D models, can facilitate rigorous analysis of drug interactions over the entire clinical dose range, using microcomputers and sophisticated graphics programs. This direct and pragmatic method offers investigators a practical new tool with which to analyze drug combinations for cancer chemotherapy.

Interferon-gamma-inducing factor gene transfection into Lewis lung carcinoma cells reduces tumorigenicity in vivo

To investigate the immunoregulatory effect of murine interferon-gamma-inducing factor (mIGIF), we transfected Lewis lung carcinoma (LLC) cells with a mammalian expression vector containing the mIGIF complementary DNA. The culture medium of the transfectant cells stimulated interferon-gamma (IFN-gamma) production by spleen cells in vitro in the presence of anti-CD3 antibody and markedly potentiated the effect of interleukin-12 (IL-12) on IFN-gamma production by spleen cells. mIGIF transfectant cells showed reduction of tumorigenicity and induction of an in vivo immuno-protective effect against the parental LLC cells. To examine the combined effect of systemic administration of recombinant IL-12 (rIL-12) and local mIGIF on the tumorigenicity, mice were challenged with LLC or transfectant cells on day 0, and the tumor-bearing mice were injected with 50 ng of rIL-12 intraperitoneally from day 7 to 11. Systemic rIL-12 showed an anti-tumor effect. However, mIGIF gene expression did not potentiate this effect of systemic rIL-12 in vivo.